Q Dear Doc, I am very scared about something I was diagnosed with recently. I went to see my doctor simply because I was having problems with my period that had become irregular, and ended up finding out I have a brain tumour, which is what was causing it.

I want to take it out because I don't want something growing in my brain, but my doctor said it's not necessary, and, instead, gave me medication to help with the periods. I really cannot figure why though... I don't want to wait until it's huge and hard to move, and end up a vegetable! Do you think I should get a second opinion and have another doctor move it?

A Based on what you have described, it sounds as though you were diagnosed with a prolactin-producing pituitary adenoma. It has always been an interesting diagnosis, resulting in the panic and confusion in patients that I assume you are now having, so let me start off with the basics.

The pituitary gland is a small gland in the middle of the head just below the brain. The gland contains cells that produce a hormone called prolactin. This hormone is responsible for stimulating the production of breast milk (lactation).

A prolactin-producing pituitary adenoma, also called a prolactinoma, is a benign (non-cancerous) tumour of the pituitary gland that produces prolactin. They cause symptoms, either from the increased levels of prolactin interfering with the function of the ovaries, or less commonly, when the adenoma grows large enough to compress the pituitary gland or nearby structures in the head.

Prolactinomas can be successfully treated with medication alone. The medications lower the prolactin level in the blood substantially, often to normal values, and usually reduces adenoma size.

However, a small minority of these adenomas do not respond to medication and must be treated with surgery or, less commonly, radiation therapy.

As mentioned before, the symptoms of prolactinomas fall into two categories: those that result from elevated prolactin levels, and those that result from compression caused by the tumour.

Symptoms caused by elevated blood prolactin

Elevated prolactin levels interfere with the function of the ovaries. When a high blood prolactin concentration interferes with the function of the ovaries, secretion of estrogen decreases. This results in irregular or absent menstrual periods, infertility, menopausal symptoms (hot flashes and vaginal dryness) and, after several years, osteoporosis (thinning and weakening of the bones). High prolactin levels can also cause milk discharge from the breasts.

Symptoms caused by compression

Large adenomas can cause symptoms by pressing on nearby structures in the head. Pressure on the nerves to the eyes can impair vision, especially the peripheral (side) vision. Pressure on the pituitary gland can result in decreased production of the hormones that stimulate the thyroid gland and the adrenal glands, leading to underactivity of those glands. Pressure can also cause headaches.

The aim of treatment is to lower the level of prolactin in the blood to normal, and to decrease the size of a large adenoma, especially if it is compressing surrounding structures.

Not all prolactinomas require treatment. If the tumor is large or causing symptoms, it should probably be treated, but if it is small and is not causing symptoms, it does not need to be treated.

When treatment is necessary, most prolactinomas respond well to therapy with medications called dopamine agonists. If an adenoma does not respond to any of these types of medications, or if the medication causes intolerable side effects, other treatment options should then be considered.

Surgery becomes an option when dopamine agonists are ineffective or not tolerated. Surgery may also be the best choice for a woman with a very large tumour that is not entirely responsive to medication, and who wants to become pregnant, because during pregnancy the adenoma may grow.

It is important that the doctor and patient discuss the possible benefits and risks of each treatment option and formulate a management plan.

Now that you know a little more and, hopefully, are a little less anxious, it would be a good idea to return to your doctor and have that discussion.

Q Dear Doc, my mother was recently diagnosed with arthritis, and she INSISTS on exercising, saying she has to work out the knee. Should people with arthritis really be exercising? Please help.

A Well, like the popular saying goes, 'mother is always right', and in this situation, she is.

Yes! People with arthritis should exercise. Regular exercise can help reduce the pain of arthritis, even though it might be painful at first.

Since you are obviously concerned, here's how you can help. Visit with her doctor and ask if there are any exercises she should avoid, and also ask if she should see a physical therapist before starting to exercise.

Ensure she tries to exercise about 30 to 40 minutes a day, on most days of the week, and not overexert herself. If she can't exercise for 30 to 40 minutes at a time, she should break up her exercise into shorter sessions.

Here are some other tips that will allow her to exercise safely with her arthritis:

- Start slowly and gradually increase the exercise programme.

- Take 10 to 15 minutes to warm up before exercising. Warm-up can be walking slowly, marching on the spot, or stretching the muscles.

- If she is using weights, start with lighter weights and slowly increase them.

Ensure she protects her joints when exercising by:

- Walking on a flat surface, especially if she has hip, knee, foot, or ankle problems.

- Wearing shoes that support and cushion her feet.

- Paying attention to pain - if she has pain, she should stop or change what she is doing.